Electrical interlock



ELECTRICAL INTERLOCK Filed 0d. 2, 1950 I/III/IIIII/I 5 2,752,413ELECTRICAL INTERLOCK Arthur H. Junkins, Geneva, 11]., assignor toAdmiral Corporation, Chicago, 111., a corporation of DelawareApplication October 2, 1950, Serial No. 187,866

3 Claims. (Cl. 174-50) This invention relates to interlock switchdevices for use in conjunction with high voltage power supply fortelevision receivers whereby contact by an unauthorized person isprevented as long as the safety device is in a predetermined or normalposition.

More specifically, the interlock device is particularly adaptable of usein conjunction with one of the sides of a television receiving sethoused in a cabinet which side is removable. The outer wall member bearsa pair of terminals, at the end of a power supply cable, which areadapted to cooperate, electrically, with another pair of terminals, infixed relationship to an inner housing or cabinet, and in electricalconnection with the high voltage producing means. The safety device isone of at least two elements of an inner cowling or housing providing,while in a normal position with respect to the other of the elements, anenclosure for the high voltage producing means within the cabinet.Furthermore, the safety device is movably anchored to another and fixedelement of the cowling for movement away from its normal position sothat access can be had to the high voltage producing means.Additionally, the normal position of the safety member is in such closeproximity to the outer cowl member that it is necessary to completelyremove said outer cowl member from the cabinet, thereby disconnectingthe respective pairs of terminals from each other, before the safetymember can possibly be moved substantially away from its normal positionto afford access to the high voltage producing means.

In television receiving sets of earlier construction a practice, amongothers, has been to run a power conducting supply line directly to thechassis, to which the line was rigidly anchored and from whence leadscontinued to the high voltage producing means. In this construction itwas essential that the supply of electric power be broken off at a pointexternally of and remote from the apparatus before access could be hadto the high voltage source, with safety. In other television receivingsets a separable connection was provided by pairs of terminals adaptedto be in complementary relationship to each other to provide forconveyance therethrough of an electric current from a suitable source tothe high voltage producing apparatus. This second construction involvedmounting one of the pairs of terminals on a cowling associated with thehigh voltage apparatus while the other of the pairs of terminals were ona cowling or removable foraminous wall, usually at the back of thecabinet. Since the foraminous wall was slightly resilient, it waspossible for a portion of the wall to be loosened at one of its edgesand bent away from the cabinet sufficiently for insertion of ones arminto engagement with high voltage conducting surfaces without firstdrawing one pair of terminals out of electrically conductive engagementwith the other pair of terminals.

The present invention overcomes the foregoing disadvantages by use of asafety or interlocking member which plays the double role of affordingcowling means, adapted to cooperate with other cowling means to envelophigh nited States Patent 2 voltage producing apparatus, a supply currentto which must be discontinued before access can be gained to theapparatus. Furthermore, the safety member enables the apparatus, in itsentirety, to comply with requirements of the United States Board of FireUnderwriters.

Another advantage is the matter of convenience in mass production and/orservicing of television apparatus in which this device is included sinceone of the pair of terminals is supported within, and independently of,the inner cowling which is adapted to be added to assembly aftersoldered connections have been made. By such a construct-ion the innercowling is also adapted to be removed from the high voltage producingmeans when and if disassembly is advisable, without the necessity ofcutting or unsoldering leads from the high voltage producing means.

Other advantages of the invention will be set forth in part hereinafterand in part will be obvious herefrom, or may be learned by practise withthe invention, the same being realized and attained by means of theinstrumentalities and combinations pointed out in the appended claims.

The accompanying drawings illustrate one embodiment of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

Fig. 1 is a fragmentary elevational view of a cabinet for a televisionreceiving set, the same being broken away to reveal the inner cowlingfor the high voltage producing apparatus;

Fig. 2 is a view similar to Fig. l, the cowling being shown in openposition;

Fig. 3 is a fragmentary exploded view, partly in section and partly inelevation;

Fig. 4 is a fragmentary elevational view of the end of the cowling inopen position; and

Fig. 5 is a section taken on line 55 of Fig. 4.

In Figs. 1 and 2 the reference character 6 is used to denote a cabinet,in which is housed apparatus, not shown, such as used for televisionreception which must be operated by a high voltage current. One of thesides of the cabinet, usually the back, is at least partly closed by aremovable wall or outer cowling 7. This wall is of any suitable materialand is usually foraminous in structure to afford a flow of air:therethrough so that heat generated within the cabinet may be readilydissipated. Although the television apparatus per se is not shown, it issupported by a frame or chassis 8 within cabinet 6. Chassis 8 carrieshigh voltage producing apparatus, part of which is indicated by thecharacter 9, and an inner housing member 11 to partly enclose the highvoltage producing apparatus.

Details of the structural features of the safety member include aterminal fixture 12 (Fig. 1) comprising male and female compositecoupling elements 13 and 14 (Fig. 3). The element or plug 13 is carriedby the wall 7 while the element 14 is supported, from the chassis 8, bya bracket 16. The element 14 includes terminal plugs or prongs 17 whichare coupled by leads 18 to the high voltage producing apparatus 9 andare adapted to be received in sockets 19 to which a supply cable 21 isin electrical communication. The element 13 may take the form of anysuitable fixture, the sockets 19 of which are substantially encased inrubber 22 which may be an integral part of the insulation of cable 21.Additionally, the rubber extends laterally in the form of flanges orears 23 through which rivets 24 extend, to rigidly secure the element 13to the outer cowling 7. When the prongs are in cooperation with thesockets 19 the outer cowling 7 is adapted to be attached to the cabinet6 by a series of screws 26, one of which is shown in Fig. 3 forextension through one of a series of holes 27 at the edges of thecowling.

The inner cowling 11 may be bolted to the chassis and includes verticalside walls 28, in parallel relationship to each other. Walls 28 extendfrom a vertical front wall, not shown, to flanged rear edges 29 inextension toward each other. The top and rear end of the cowling 11,although open, may be closed by a movable cover member 31 which is Lshaped in vertical section (Fig. 2). Member 31 performs the function ofa safety or interlocking member and includes, at the edges thereof,flanges 32 which add rigidity to said member and are adapted to embracethe sides 28. Continuations of the flanges 32 provide a pair of arms 33at the lower end of the cover which are ivoted at 34 to the walls 28 sothat cover 31 is adapted to be swung from the enclosing or normalposition in which it is indicated in Fig. 1, to the extreme openposition indicated in Fig. 2 wherein access may be had to the apparatus9 through the top and end of cowling' 11.

As was previously indicated, the female socket 14 is carried by thebracket 16. Said bracket includes a base portion 36 which is preferablybolted to the chassis S. It is offset transversely of itself at 38 inorder that it may extend behind the cover member 31 when said covermember is closed. It has a socket carrier portion 37 at its upper endwhich is bifurcated by a notch 39. A terminal cup or socket 43. havingears 42 overlaps the carrier portion to which said cup is riveted at 43.The bottom of the cup 41 is formed with an opening 44, the edges ofwhich provide flanges that are sandwiched between plates of insulatingmaterial 46 and 47 through which the terminals 17 extend. The edges ofplate 47 closely register with the internal wall surface of cup 41.Consequently, the pins 17 are retained against lateral displacementwhile clamping pressure applied to plates 46 and 47 by collars 48 andupset portions 49 retain the termi nals against axial displacement withrespect to bracket 16.

It will be apparent that the high voltage producing apparatus can beassembled in combination with the chassis, the terminals 17 and solderedconnections made before said apparatus is enclosed by the cowlingmembers 11 and 31. Should an occasion arise wherein replacement of somepart of the high voltage producing apparatus is necessary, the same mayconveniently be effected by unbolting the cowling and removing it fromthe chassis 8 without the necessity of first breaking solderedconnections.

In order that the prongs 17 may cooperate with the sockets 19, the covermember 31 has an aperture 51 therein through which the element 13 isadapted to extend when the member 31 is in its normal or closedposition. The aperture 51, however, is in a rectangular ofiset region52, of member 31, which is distended outward to accommodate outwardlyprotruding portions of the mechanism just referred to.

Although the clampingaction of screws 26 are adequate to retain theterminals 17 and 19 in operative engagement with each other, additionalmeans, if desired, may also be used to retain the terminals inengagement with each other. The additional means may take the form of ascrew 53' adapted to pass freely through a hole 56 in the outer cowlingand be threaded in a second hole 54 in the cover 31. While cover 31 isso disposed, its swingable end may be further retained in closedrelationship with respect to the housing 1-1 by a resilient clasp orhook 57 on the end of said cover, the clasp being, adapted to snap downover the rear of housing 11 as cover 31 is closed.

In the operation of withdrawing the terminal plug 13 from engagementwith the terminal socket 214, there is a tendency to bend the bracket 16outwardly owing to the retentive engagement of the pins 17 by thesockets 19. This tendency is resisted because the carrier portion 37includes a pair of offset ears 53 that extend behind the flanges 29,flanges 29 thus limifing' deflection of bracket 16 outwardly of housing11,

As will now be apparent, it is impossible to gain access to the highvoltage producing apparatus without swinging the cover 31 to asubstantial degree, about its pivot axis 34, from the normal position ofsaid cover. The operation of swinging the cover can be carried out onlyafter the plug and socket 17 and 19 have been disengaged from eachother. This precludes the possibility of access to the space within thecowling members 11 and 31 by merely removing enough of the screws 26 toenable the wall 7 to be bent away from one corner of the cabinet.

Although I have thus described my invention, I am also aware thatnumerous and extensive departures may be made therefrom withoutdeparting from the spirit or scope of my invention.

If the cover is opened inadvertently or intentionally, the act ofopening stops the plug from the socket and disconnects the power line.Furthermore, even if the rivets that hold the plug onto the rear wallshould be removed so that removal of the wall does not remove the plug,there is still the element of safety due to the fact that the coverengages the plug and stops it from the socket.

I claim:

1. The combination with television equipment housed in a cabinet one ofthe sides of which is open and the equipment includes a frame forsupport of high voltage producing apparatus collectively enveloped bymovable and fixed inner cowl members within the cabinet, of a first pairof terminals, bracket means on the frame to sup port the terminalsindependently of said Cowling and in electrical communication with thehigh voltage producing apparatus, an outer cowl member to at leastpartly close the open side of the cabinet, said outer cowl member whenclosing the cabinet being adapted to lock the movable cowl memberagainst opening, a second pair of terminals carried by the outer Cowlingat the end of a supply cable, said second pair of terminals beingadapted to extend into electrical communication with the first pair ofterminals when the opening is closed by the outer cowl member, openingof said inner cowl thereby being possible only after said outer cowl hasbeen removed from the cabinet and one of the pairs of terminalsconcurrently disengaged from the other pair of terminals, first stopmeans in connection with said bracket means, and second step means inconnection with the fixed inner cowl member, said respective stop meansbeing adapted to cooperate with each other when one of the pair ofterminals is disengaged from the other pair of terminals to resistpermanent deflection of said bracket means.

2. The combination with television equipment housed in a cabinet one ofthe sides of which is open and the equipment includes a frame forsupport of high voltage producing apparatus collectively enveloped bymovable and fixed inner cowl members within the cabinet, of pivotalmeans to pivotally anchor the movable cowl member to the fixed cowlmember, a first pair of terminals, bracket means on the frame to supportthe terminals independently of said cowling, said terminals being inelectrical communication with the high voltage producing apparatus whileso supported, an outer cowl member to at least partly close the openside of the cabinet, said outer cowl member when closing the cabinetbeing adapted to lock the movable cowl member against rotation to anopen position, a second pair of terminals carried by the outer cowlmember at the end of a supply cable, said second pair of terminals beingadapted to extend into electrical communication with the first pair ofterminals when the opening is closed by the outer cowl member, openingof said inner cowl thereby being possible only after said outer cowl hasbeen removed from the cabinet and one of the pairs of terminalsconcurrently disengaged from the other pair of terminals, first stopmeans in connection with said bracket means, and second stop means inconnection with the fixed inner cowl member, said respective stop meansbeing adapted to cooperate with each other when one of the pair ofterminals is disengaged from the other pair of terminals to resistpermanent deflection of said bracket means.

3. The combination with television equipment housed in a cabinet one ofthe sides of which is open and the equipment includes a frame forsupport of high voltage producing apparatus collectively enveloped bymovable and fixed inner cowl members within the cabinet, of pivotalmeans to pivotally anchor the movable cowl member to the fixed cowlmember, latch means on said movable cowl member to releasably securesaid movable cowl member to said frame, a first pair of terminals,bracket means on the frame to support the terminals independently ofsaid cowling, said terminals being in electrical communication with thehigh voltage producing apparatus while so supported, an outer cowlmember to at least partly close the open side of the cabinet, said outercowl member when closing the cabinet being adapted to lock the movablecowl member against rotation to an open position, a second pair ofterminals carried by the outer cowl member at the end of a supply cable,said second pair of terminals being adapted to extend into electricalcommunication with the first pair of terminals when the opening isclosed by the outer cowl member, opening of said inner cowl therebybeing possible only after said outer cowl has been removed from thecabinet and one of the pairs of terminals concurrently disengaged fromthe other pair of terminals, first stop means in connection with saidbracket means, and second stop means in connection with the fixed innercowl member, said respective stop means being adapted to cooperate witheach other when one of the pair of terminals is disengaged from theother pair of terminals to resist permanent deflection of said bracketmeans.

References Cited in the file of this patent UNITED STATES PATENTS1,071,797 Roche Sept. 2, 1913 2,439,708 Abraham Apr. 13, 1948 2,497,487Cain Feb. 14, 1950 FOREIGN PATENTS 561,831 Germany Oct. 20, 1932 469,289Great Britain July 22, 1937

